Originally Posted by Secret Squirrel
Is there any real way to tell factory fitted heads compared to over the counter items?
I have a pair which have some stampings(some numbers and a big HC on each end)on the end and appear to have had 2 studs cut down on each head (screwed into intake ports from the block mating surface)
Dates are 7\3\69 and 2\28\69
Those were 69 ZL1 or L88 heads. Also used on 1971 LS6. Going by the dates they very well could be factory fitted. They sold a lot of these over the counter to the drag racers. If you wanted to build a hot big block back then these were the head to have. The open chamber design unshrouds the valves better than the closed chamber design. No way to tell if they are over the counter or factory as far as I know.